Danny Cohen is a man in a hurry. Not yet 40, he has just been appointed the BBC's director of television - responsible for all four main BBC TV channels, as well as all in-house TV production, from Doctor Who to Strictly to EastEnders.

It is a big and powerful job – arguably the biggest and most powerful in British TV - with an overall commissioning budget somewhere north of £1billion a year. Cohen beat off competition from other senior BBC executives, not least Peter Salmon, director of BBC North. Salmon has moved a huge chunk of the BBC to Salford without a hitch when many said it would be a disaster — and nobody who works with him has a bad word to say about him.

By contrast Cohen, whether fairly or unfairly, has a reputation in the industry for being fiercely ambitious. He cut his teeth at Channel 4, where he was in charge of Big Brother in its heyday, before moving to the BBC as controller of the youth TV channel BBC Three.

His appointment completes the senior team of the new director-general, Tony Hall. It seems that Hall is intent on passing the baton of BBC management to the next generation of talented executives, having appointed the almost equally fresh-faced James Harding as the corporation's director of news.

If anything, Cohen has been a little too youth-focused at BBC One: Fearne Cotton helping to present the Jubilee coverage was a mis-step. The Voice, too, struggled to hold viewers' interest in its first series last year, because its stock-in-trade — transformative stories of ordinary kids becoming singing stars — belongs so firmly to ITV.

He has also been fiercely competitive with ITV in his schedules. Cohen moved the final series of Spooks to Sunday nights to put it up against Downton Abbey, and tried to spoil the opening of ITV's Broadchurch by pitting it against BBC One's very similar drama, Mayday.

What Cohen needs to show in his new job is that he truly understands the BBC's role as a public service broadcaster. He could make a useful start by reversing some of the appalling vandalism that the BBC Trust and senior BBC management have recently wreaked on BBC Four, forcing it to ape Sky Arts and eviscerating it of its marquee drama output.

BBC Television also needs to recognise that ITV viewers are licence-fee payers too, and that dog-eat-dog competition helps nobody.

Perhaps Cohen's most important colleague is BBC Two's quietly brilliant controller Janice Hadlow. She took over a channel that was an undefined hotchpotch, and has turned it into a consistently compelling, accessibly brainy offering that frequently breaks new TV ground — not least with its live factual strands such as Stargazing Live and popular formats such as The Great British Bake-Off.

And Cohen's most important challenge — initially at least — is finding someone to replace him as controller of BBC One. Two people who would be obvious contenders (ITV's Peter Fincham and C4's Jay Hunt ) have already been BBC One controller, leaving the field wide open. But then again a little experience, to complement Cohen's youth, wouldn't be a bad idea.